Dunnage bars have many uses and may, for example, be used as part of a rack for transporting metal stampings such as automotive vehicle door panels, hoods and rear deck lids. An example of a rack for transporting metal stampings is own in prior U.S. Pat. No. 5,876,165 which is assigned to the assignee of this application.
Often a rack carrying metal stampings is shipped by train. When the train starts or stops suddenly, the dunnage bar may be subjected to severe impact. The dunnage bar must be strong enough to withstand the impact without twisting or bending.
The dunnage bar of the present invention is an elongated, tubular member having an inner wall, an outer wall and two side walls. Reinforcement of the dunnage bar is provided by an elongated channel extending lengthwise within the bar. The channel has a bottom wall spaced from and parallel to the inner and outer walls of the dunnage bar and side flanges secured to the side walls of the dunnage bar. The channel and the inner wall of the dunnage bar define a pocket for receiving a dunnage strip. The dunnage strip has a nose projecting outwardly through a slot in the inner wall of the dunnage bar. The dunnage strip is usually made of a suitable plastic or elastomeric material and its nose engages the metal stampings and holds them in place. The bottom wall of the channel has laterally spaced flat portions disposed in a common plane, separated by a strengthening, trough-shaped portion displaced downwardly from the common plane of the flat portions of the bottom wall. The special configuration of the bottom wall of the channel greatly increases the strength of the channel and hence of the dunnage bar, and increases it resistance to twisting and bending.
Preferably the trough-shaped portion of the bottom wall of the channel is concavo-convex in cross-section having a concave side facing upwardly and a convex side facing downwardly. In a preferred construction, the trough-shaped portion of the .channel is arcuate. Preferably also, the space defined by the channel and the side walls and bottom wall of the dunnage bar is completely open and devoid of structure except for the trough-shaped portion of the bottom wall which projects downwardly into
One object of this invention is to provide a dunnage bar construction having the foregoing features and capabilities.
Another object is to provide a dunnage bar construction which is composed of a relatively few simple parts, is rugged and durable in use, and is capable of being inexpensively manufactured and assembled.
These and other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.